Russia appeared to rule out Iran's membership in a Central Asian regional security bloc on Friday, saying countries under UN sanctions could not join the Shanghai Cooperation Organization. Two days after backing sanctions against Iran in the UN Security Council, Moscow signalled at the annual summit of the six-nation SCO that it was moving towards the West's stronger position on restraining Iran's nuclear ambitions. The Kremlin suggested it might also forego selling missiles to Tehran. Iran has observer status within the SCO and its president, Mahmoud Ahmadinejad, has upstaged previous events. In a snub to the West at last year's meeting, SCO leaders congratulated him on a disputed election victory. Ahmadinejad did not travel to this year's meeting in the Uzbek capital Tashkent. Russian Foreign Minister Sergei Lavrov said the Iranian leader had been invited but declined to attend. Members of the SCO, led by Russia and China, were expected to approve new rules on membership of the body, which focuses on security issues in Central Asia. Ex-Soviet states Kazakhstan, Kyrgyzstan, Uzbekistan and Tajikistan are also full members. “If the Security Council has imposed sanctions, such a country cannot become a full member,” Lavrov told reporters, making no specific reference to Iran. Iran was represented by its foreign minister, Manouchehr Mottaki, who described the latest UN sanctions as “unfair and devoid of legal grounds”. In a speech to the summit he said Iran was “above political games”. Sanctions hurt Russia-Iran relations The Security Council voted on Wednesday to impose a fourth round of sanctions on Iran over its nuclear programme, which Western countries suspect aims to develop an atom bomb. Iran says its nuclear program is peaceful. Russia and China, veto-wielding UN Security Council members, worked to water down the sanctions against Iran, but voted in favour of them. Moscow's support for the sanctions has soured its traditionally close ties with Iran. A Kremlin source, speaking on condition of anonymity, said the UN sanctions preclude Russian sales of S-300 surface-to-air missiles to Iran. Moscow had in the past maintained it could sell the missiles to Tehran despite strong objections from Israel and the United States. Ahmadinejad on Tuesday warned the Kremlin against siding with “Iran's enemies” in supporting sanctions. The Kremlin reacted to similar comments in May by telling Iran's leader to refrain from “political demagoguery”.